U.S. Pat. No. 3,333,831 teaches a power driven fluid displacement apparatus which has an electric drill driving a mixer attachment which is attached to the clutch of the drill by a long shaft. The mixer attachment is intended to be downwardly inserted into a container or barrel holding the medium to be mixed. Two blades are disposed on the end of the shaft, 180.degree. apart. Each blade has an outer pushing part having leading and trailing edges bent upwardly or away from the part towards the shaft. The blades are twisted so that the leading edge is higher than the trailing edge. Thus, when the shaft is rotated in a given direction, an axial downward force is produced because the fluid is pushed downwardly away from the shaft. Obviously this force can be sufficient to support the weight of an electric drill, making mixing a somewhat relaxing process. However, because of the upwardly bent blades, one finds it difficult to agitate the fluid medium which has settled at the lower circumferential corner of the container.